Numbers 19:11, 16, 18

“Whoever touches the dead body of any person shall be unclean seven days.

Whoever in the open field touches someone who was killed with a sword or who died naturally, or touches a human bone or a grave, shall be unclean seven days.

Then a clean person shall take hyssop and dip it in the water and sprinkle it on the tent and on all the furnishings and on the persons who were there and on whoever touched the bone, or the slain or the dead or the grave.